instructing the crew to build a makeshift rig they called the mailbox, to purge the deadly gas from the craft and keep oxygen levels safe. this bought some time for the crew, who were barely breathing and running low on water. you lost 14 pounds? >> i didn't realize i'd lost 14 pounds. and i guess, you know, i was all charged up. >> they were sick, freezing, and tired, but safe for now. mission control's next task was to get the broken-down craft out of a lunar landing course and back on a free return to an earth trajectory. engineers in houston figured the crew could do this by executing two separate burns, or accelerations, made from the limping command module. towering that up after the long, cold sleep was one of mission control's greatest achievements. flight controllers generated the necessary procedures to do this in three days. something like that would normally take three months.